A numerical study of double-diffusive flow in a long rotating porous channel

The problem of double-diffusive flow in a long rotating porous channel has been analysed numerically. The two opposite vertical walls of the channel are maintained at constant but different temperature and concentration, while both horizontal walls are kept insulated. The generalised model is used to mathematically simulate the momentum equations with employing the Boussinesq approximation for the density variation. Moreover, both the fluid and solid phases are assumed to be at a local thermal equilibrium. The Coriolis effect is considered to be the main effect of rotation, which is induced by means of the combined natural heat and mass transfer within the transverse plane. The governing equations are discretised according to the finite volume method with employing the hybrid differencing scheme to calculate the fluxes across the faces of each control volume. The problem of pressure-velocity coupling is sorted out by relying on PISO algorithm. Computations are performed for a wide range of dimensionless parameters such as Darcy-Rayleigh number (100 <= Ra* <= 10,000), Darcy number (10(-6) <= Da <= 10(-4)), the buoyancy ratio (-10 <= N <= 8), and Ekman number (10(-7) <= Ek <= 10(-3)), while the values of Prandtl and Schmidt numbers are maintained constant and equal to 1.0. The results reveal that the rotation seems to have a dominant role at high levels of porous medium permeability, where it reduces the strength of the secondary flow, and hence the rates of heat and mass transfer. However, this dominance decreases gradually with lessening the permeability for the same level of rotation, but does not completely vanish.